This is a nice loop if you're looking for quiet trails, great views, vigorous scrambling and close to seattle. I didn't see a single human being, even in the usually busy Ira Spring Trail parking area. I like the quiet trails so the dogs can run around and be dogs and not bother anyone. Park at Ira Spring lot and follow the trail for about a half mile to the first hairpin turn to the right. You'll see an unmarked trail straight ahead at the turn, take it. After a mile or so of gentle slopes, you'll come to a Y. The lower fork to the left goes off toward Dirty Harry's Balcony or points lower (i don't know for sure). The right fork takes a switchback up hill. Take it. You'll switchback more steeply though a nice 2nd growth forest. As the trail climbs and leave the woods, the trail peters out, but the way is clear - up the spine. This turns into a nice class 2 scramble to Putrid Petes peak and W Defiance Ridge. I've always wanted to walk the length of the ridge, but had been turned around by rain. Today was perfect, sunny and light breeze which kept the bugs away, so we went to the high point on the west end of the ridge (I don't know if it has a name), signed a summit register there (or a geocache log?) and then headed back along the ridge toward Mt Defiance. Stay on the ridge as you enter the trees again and you'll come to Mt Defiance trail (again the trail kind of fades away shortly before the intersection, just stay on the ridge). Take a right on the Mt Defiance trail and follow it across the face of Mt Defiance (or take a side trip and bag Mt Defiance along the way, the trail is an up hill spur about fifty yards from where you got on the trail). It was getting late so me and the pooches headed down the trail to mason lake. I decided to take the old trail along mason creek, which you can find about 100 yards past the outlet of mason lake. Look for a pile of bleached looking looks piled in an unnatural looking array on your right. turn there and hop a blow down and you're on the trail. This trail is steep, rooty, and muddy in places, but most of it is really pretty. You eventually hook up with the Ira Spring trail and back to the parking lot. About 3600' of gain and my round trip was 7.5 hours, although I lingered for a long time on the ridge. Bring water. Until you get to mason lake, there is only one small creek running right now, about a third of the way up PPPeak. Lots of sun exposure. Great hike on mostly unmaintained, but very nice, trails.